The cover is showing HM Queen Elizabeth II trooping the colour. The sheet consists of 11 Machins and a London 2010 label. This is the majority of the current (sheet) non self adhesives that will be on sale on the day of issue ( May 8th). This particular product will be produced by BFDC.
A nice mini sheet I think, my opinion though, a shame about the post marks they spoil it a little. I bet Ian will do better.
The covers will be £20.00 a pop (again) a bit on the expensive side for my taste, even though they (the covers) are limited to 50 numbered copies. The actual sheets (mint) retail at face value £5.05p if you purchase them via Royal Mail.
As a final thought, I am also pleased I no longer collect se-tenant pairs A total of 17 (vertical and horizontal pairs) on this sheet. I wont bother doing the math of how much it will cost, or how many sheets you will need to obtain them all.